Subtypes of depressive symptoms and inflammatory biomarkers: An exploratory study on a sample of HIV-positive patients

Abstract

Depressive symptoms cause major impairment and may accelerate HIV progression despite the use of antiretroviral medication. The somatic symptoms criteria for HIV infection and depression partially overlap, which can make differential diagnosis challenging. Because of chronic inflammation caused by HIV infection, HIV-positive patients may develop somatic and affective-cognitive symptoms of depression. Inflammation-related depression is primarily characterized with severe somatic symptoms such as fatigue and sleep disturbance. This study sought to explore the patterns of somatic and cognitive-affective depressive symptoms that characterize HIV-positive patients. Our specific aims were (1) to identify subtypes of depressive symptoms in a sample of HIV-positive patients; and (2) to test the subtypes' difference on inflammatory and HIV disease progression biomarkers. HIV-positive men and women (N=102) with and without depressive symptoms were randomly selected from an Italian HIV clinic. Depressive symptoms (PHQ-9), viral load (VL), CD4+, Il-6, TNF-α, and monocytes were assessed. The three subtypes formed using Latent Class Analysis (LCA) identified patients with (1) severe cognitive-affective and somatic depressive symptoms; (2) severe/moderate somatic symptoms; and (3) absent or low depressive symptoms. The subtype with severe/moderate somatic symptoms was characterized with elevated levels of Il-6 and monocytes. No difference on HIV progression biomarkers was found. The subtypes of depressive symptoms might help differentiating depressive symptoms from HIV- and inflammatory-related somatic symptoms. When present, cognitive-affective and/or somatic symptoms cause significant impairment to patients' lives and thus warrant further assessment and treatment.

Keywords: Depression; HIV; Il-6; Monocytes; Somatic symptoms.

Fig. 1. PHQ-9 item conditional probabilities – histograms

Conditional probabilities: class-specific probability of each PHQ-9 item’s answer (i.e. 0-Not at all, 1-Several days, 2-More than half the days/Nearly every day) to be endorsed.

Fig. 2

Levels of inflammatory biomarkers by depressive symptoms subtypes (latent classes).